Rock drill



E. J. SMITH ROCK DRILL Filed Dec. 12,- 1925 IN VEN TOR EJSMITH &@

.ATTOBN 5' Patented July 7, 1925.

UNITE STATES. PATENT ornca.

EDWARD J. SMITH, 0F CHATEAUGUAY BASIN, QUEBEC, CANADA, A'SSIGNOR OF ONE- HALF T0 GEORGE A. IRWIN, OF MONTREAL, QUEBEC, CANADA.

nocx DRILL.

Application filed December 12, 1923. Serial No. 680,194.

To all whom it may concern:

Be it known that I, EDWARD J. SMITH, a subject of the King of Great Britain, and resident of the village of Chateauguay Basin, in the Province of Quebec and Dominion of Canada, have invented certain new and use ful Improvements in Rock Drills, of which the following is a full, clear, and exact description.

This invention relates to new and useful improvements in rock drills or the like, and the object of the invention is to provide a drill having removable bits or cutters which will be simply and easily attached to the drill head.

Another object is to provide a rock drill which will be simple and inexpensive and which will also be etlicient in operation.

In my invention, I provide a drill steel or shank and a head formed integral with the shank, said head being provided with a plurality of wings. In the wings are formed recesses adapted to receive removable bits or cutters, the retaining portions of the cutters being adapted to fit tightly in said recesses. The upper surfaces of the cutting portions of the cutters are of such shape that the surfaces of the wings are entirely covered. The cutters are adapted toextend beyond the outside edge of the wings to form a clearance for the loosened rock between the wall of the hole and the head. Means are also provided to supply air or water to the cuttingsurface and the bits or cutters are so arranged that they interlock at the centre.

In the drawings Fig. 1 is a partial elevation of a drill shank and head.

Fig. 2 is a partial elevation of the shank and head of a drill with the cutters attached.

Fig. 3 is a plan view of the head.

Fig. 4: is a side elevation of one of the cutters.

Fig. 5 is a plan view of one of the cutters.

Fig. 6 is an end elevation of the cutter.

Fig. 7 is a side elevation of another of the cutters.

Fig. 8 is a perspective view of the head of the drill withthe cutters in position.

Referring more particularly to the drawings, 11 designates a drill shank having the head 12 formed integral therewith. The head is formed with a plurality of extend ing arms or wings 13, the faces 14 of which lie at right angles to a line passing through the centre of the shank in the longitudinal direction. The head of the drill may be made larger in diameter than the diameter of the shank. The face 14 of the head of the drill is provided with recesses 14?, which extend across the face from edge to edge. Into the recesses are driven the cutters 15 and 15, details of which are shown in F igures 4 to 7 inclusive. The retaining portions 16 of the cutters are adapted to fit into the recesses. The retaining portion is shown of dovetailed formation and is adapted to-fit into dovetailed recesses, as shown in Figure 2, but this may be modified without departing from the spirit of the invention. The cutting portion 17 of the cutters or bits is triangular in section, the apex 18 of the triangle forming the cutting edge, while the base 19 is made wide enough to cover the face of one of the wings, so that when all the bits or cutters are mounted in the head, the under surface or face of the wings is entirely covered. The cutters are made a light driving fit in the recesses and are held from movement by frictional engagement with sides 20 of the recesses. The cutters when mounted are adapted to extend slightly beyond the edges of the wings, as shown in Figure 2, and are slightly bevelled at the exposed edge 21 to provide a clearing edge for loosened rock or dirt. The cutters are interlocked in the centre of the drill, part of two of the cutters being cut away to form shoulders 22 against which the'other cutters buttto prevent movement across the face of the bit when boring at an angle.

A detail of the shouldered cutters is shown in Figure 7 and a perspective view showing the method of mounting is shown in Figure 8. The cutters do not extend across the face of the head but are spaced from one another at the centre, as shown in Figure 8 and designated 23, to allow for the insertion of a chisel, drift or like tool to release the cutters when they become blunt or'worn. The

space also allows air or water, fed through the centrally disposed hole 24 formed in the shank, to have an unobstructed passage to the cutting face ofthe bits.

The operation of the device is as follows The shouldered cutters are first driven into the recesses and the plain cutters are then driven in .o the remaining recesses until their inner ends engage with the shoulder portions of the first mentioned cutters, thereby leaving a space between them at the centre. Air or water fed through the hole formed in the drill has thus an unobstructed passage to the cutting face of the bits. The cutters, being adapted to cover the face of the wings, prevent loosened rock from coming in contact with the face of the wings, thereby preventing said loosened material from wearing away this surface. The bits also extend beyond the ed es of the wings to provide a clearance fort. e loosened material. When boring at an angle, the bits are prevented from moving across the face of the wings b one cutter pressing against the sides of the adjacent cutters, thereby forming an interlocking means for said bits or cutters,

Having thus described my invention, what I claim is 1. A rock drill comprising a shank having a head formed integral therewith, said head having s aced radially extending wings, recesses ormed in said wings, detachable cutters adapted to frictionally engage with the sides of the recesses, said cutters being of a width equal to that of the wings and of sufiicient length to extend'beyond the outer ends of the wings, and an unobstructed passageway through the shank and between the inner ends of the cutters for the passage of air or water therethrough.

2. A rock drill comprising a shank hav ing a head formed integral therewith, said head having 3 aced radially extending wings, recesses ormed in said wings, cutters having projections adapted to frictionally engage with said recesses, said cutters being of sufficient length to extend beyond the outer ends of the wings and the outer ends of cutters being bevelled, and an unobstructed passageway through said shank and between the inner ends of the cutters for the passa e of air and water.

3. A rock rill comprising ashank having a head formed integral therewith, said head having spaced radially extending wings, the undersides or faces of said wings being adapted to lie at right angles to a line passing through he centre of said shank, recesses formed in said faces, cutters having projections adapted to frictionally engage with the sides of said recesses said cutters being of sufiicient size to totally cover the faces of said wings, and an unobstructed passageway through the shank and between the cutters for the passage of water or an.

4. A rock drill according to claim 3, having triangular cutters, the apices of the triangles forming cutting edges and the bases covering the entire face of the wings.

5. A rock drill comprising a shank, a head formed integral therewith, said head having extendin wings, the lower faces of said wings belng adapted to lie at right angles to a line passing through the centre of the shank, recesses formed in the lower faces of said wings, cutters having bevelled ends and projections adapted to frictionally engage with the sides of the recesses, said bevelled ends being adapted to extend beyond the edges of said wings, means formed in the cutters to interlock them at the centre of the head, and an unobstructed passageway through the shank and between the cutters for the passage of air and water.

6. A rock drill comprising a shank, a head formed integral with the shank, said head having extending wings adapted to form a cross and the face-of said cross being adapted to lie at right angles to a line passing through the centre of said shank, recesses formed in the faces of said wings, cutters having projections adapted to frictionally engage with the sides of said recesses, part of said cutters being adapted to entirely cover the faces of the wings and extend beyond the wings, shoulders formed in two of the cutters against which the remaining cutters butt, and an unobstructed passageway through the shank and between the cutters for the passage of air or water.

In witness whereof, I have hereunto set my hand. I

EDWARD J. SMITH. 

